1. Field of the Invention
The present invention relates to a computer-implemented system for the design and development of wireless communication systems. In particular, the present invention discloses a modeling system integrated with a comprehensive set of software tools for the design, development and management of cellular telephone networks.
2. Description of Related Art
The capacity of cellular telephone systems in urban areas is typically their most precious commodity. The use of smaller cells, called "microcells," has been one of the solutions used to increase the capacity of the cellular telephone systems.
Because capacity is such a precious commodity, the design and management decisions made for cellular telephone systems are usually made to maximize the capacity of the system. For example, engineers must design the system to maximize the coverage of the geographic area with the minimum number of cell sites. In addition, interference problems must be studied so that their effect is minimized. Further, the blocking probability of each cell site must be analyzed to ensure proper call initiation.
The design of a cellular telephone system is usually performed by using modeling techniques before the system is placed in actual usage. The Lee model, described in "Mobile Cellular Telecommunications," by William C. Y. Lee, Second Edition, 1995, which is hereby incorporated by reference, is the standard model for designing a cellular telephone system. The models and the investigations performed in this area concentrate on analyzing the propagation of electromagnetic waves under a line of sight analysis.
The reflections or blocking of a direct line of sight transmission due to local terrain or man-made structures such as buildings are typically ignored during the modeling process. Ignoring the buildings and terrain effects on the transmission of radio frequency (RF) signals was assumed to be proper since cells are small. However, microcell antennas, once placed in operation, need to be adjusted in terms of placement, power output, and antenna beam patterns because the models used do not accurately predict the conditions experienced in actual use of the cellular system.
It can be seen, then, that there is a need for a better modeling tool to more accurately predict conditions present in the operation of cellular telephone systems.